A Special Issue on Archean Magmatism, Volcanism, and Ore Deposits: Part 1. Komatiite-Associated Ni-Cu-(PGE) Sulfide and Greenstone-Hosted Au Deposits: Preface(,)

Abstract

The Archean, which represents more than a third of Earth’s history, contains some of the largest and richest ore deposits of the world. Numerous cratons of variable size and age have been mapped (Fig. 1) and others are still being discovered or delineated largely due to the widespread use of high-precision U-Pb geochronology. One of the specific characteristics of Archean cratons is the coexistence and juxtaposition of different and major styles of base and precious metals deposits formed at different times and crustal levels (Poulsen et al., 2000; Groves et al., 2005a; Robert et al., 2005). Fig. 1 Global geographic distribution of Archean cratons. Map modified from Chorlton (2007) and Kjarsgaard (2007). Possible Archean crust in Central Anatolia, Turkey, from Paquette and Le Pennec (2012). It has long been recognized that Archean cratons are extremely well endowed in metals (e.g., Meyer, 1981; de Wit and Thiart, 2005), especially in komatiite-associated Ni-Cu-(PGE), greenstone-hosted Au and volcanogenic massive sulfide (VMS) deposits. Most of these deposits were formed in periods of supercontinent(s) or supercraton(s) formation (e.g., ~2800–2500 Ma Kenorland: Williams et al., 1991; Aspler and Chiarenzelli, 1998; ~2600–2200 Ma Sclavia: Bleeker, 2003). Although some of these deposit types (greenstone-hosted Au and VMS) were formed episodically at various epochs in Earth’s history (cf. Goldfarb et al., 2010), Archean examples appear to be more common, and in many cases larger and/or richer. Although common in the Archean, the deposits are not uniformly distributed among the cratons, highlighting the fact that the metal endowment of specific assemblages reflects both secular variations and craton- to district-scale controls. For example, the Yilgarn craton is very well endowed in komatiite-associated Ni deposits, in contrast to the Superior craton, which contains more significant VMS deposits. However, the study of Archean deposits …